Daeron
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Posts posted by Daeron
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Have you looked at the price of an aftermarket 2mm headgasket? http://www.thezstore.com/page/TZS/PROD/PEM09/10-2458
$160, I'll save you the trouble. If I had a turbo 280ZX in my local junkyard, I could buy the complete longblock assembly for less than that, and you are still looking at about 8:1 compression (just a hair below) with an 81 stock motor and a 2mm headgasket.
MUST KEEP OUT of high boost or those cast pistons will be holed in no time; also megasquirt is almost a must if you really want some longevity.
Honestly if I were you, I would try to MS and turbo the stock engine WITHOUT dropping the compression with the 2mm headgasket (its only around 8.6:1 as it was when it left the factory; who knows if your engine is a little worn down) and save up money for some nice new pistons and a cam. Once you hole a piston or blow something up, throw in the cam and pistons, and then when you have maxed out the potential in THAT setup you get to go bigger turbo.
Naturally you will need more fuel along the way, bigger intercoolers, hotter spark, and eventually you will want to re ring and change the bearings, may as well hog the bores out while youre at it (getting new pistons anyway right?)
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just a little more emphasis on the question.. good blue spark, NGK plugs, right???
Then check your valves, I bet you are running pretty tight. Get her good and warm, seriously.. if your temp gauge works then you can watch that and see how slow it is to come up but if its broken, let it idle for 20 minutes or so to get it HOT.
You have a manual choke lever on these carbs still right? You are keeping the choke engaged while warming up? (remember I just went through a crash course on how to actually own a carbureted car for the first time about two weeks ago, so forgive me if I am asking obvious stupid questions)
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Pull the dizzy cap and the rotor off and inspect your points. You've got good blue spark coming out of good new NGK BPR 6ES-11s right? Synchronizing these carburetors without a tool to do so (looks like a plug for the front hole but it has a little meter measuring air flow on it) is a guessing game at best, although my oldest brother is VERY good at getting it 95% of the way there just by placing both of his hands in front of the bores while the engine is running and "feeling" the air flow difference.
Warming up helps these engines run alot better as well, ESPECIALLY when the tune is a little off.
Congrats!!! Those turds are POLISHED!!!
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I am going to ask something, a detail I am not 100% clear on....
Were all cylinder heads originally the same height, from firing deck to valve cover mating surface?
I'm not even close to sure on how to verify this guess, but after poring over the photos I am going to revise my guess to say EXTREMELY shaved N42 (or variant, see BRAAP's comment about the vertical casting marks on the sides of the head below) with UNSHAVEN valves.
This head was discussed in the L6 Head ID thread, and braap had this to say on it then:
I’m not real familiar with L-series cylinder heads for other markets/countries other than domestic USA market. Though I am pretty certain that this head is NOT a domestic USA head AND it has been modified.1) Injector slots and injector manifold mounting holes along with carb mounting holes indicates post 1975 production.
2) The EFI Intake mounting holes “appear” to be 8 x 1.25mm, (Same as the carb and exhaust mounting holes), instead of the typical USDM 10 x 1.25mm, though the pictures could be deceiving and those holes could be the 10 x 1.1.25mm holes. (See picture below showing the mounting hole size difference on an US market N-42 head.)
3) In looking at the manifold face, note the 2 bolt hoes above the #6 exhaust port?…. NOT on any USDM L-6 cylinder heads.
4) Note the vertical casting lines above and between the ports in the unmachined portions of the head near the valve cover...
5) The measurement of the intake port opening means absolutely nothing in identifying that head as it had been “port matched” (opening of the port had been enlarged by hand), evidenced by sanding wrap marks left in the port entrance and the injector slots indicate most of the material removed in the intake port was removed from the roof of the port.
6) The casting number had been removed. The picture is difficult to tell but it looks like a sanding wrap finish.
7) Pics of the combustion chamber and clear well lit pics of the area surrounding the intake valve guide boss would help greatly in identifying this head, so long as the intake port work did not consist of altering the guide boss.
I looked through the Head thread for some time. I was looking for what looked, to ME, to be the most distinct feature on that combustion chamber; namely, the "heart shape" described by the second quench pad on the spark plug side of the cylinder!
It took me forever because I was focusing more on closed chamber head designs, but then I saw that the N42 heads had that sort of indentation for the valves... I don't know, maybe I am seeing things. I keep going back and forth between photographs of cylinder heads in all sorts of positions, with all sorts of lighting, at all sorts of angles, in all states of carbonation.
It seems to me that the key features in IDing it are this second quench pad (because the area around and between the valve seats looks like untouched factory to me) the flashing marks, the 8 mm bolt holes for the manifold, and lookitthat!! Those two extra holes above #6 exhaust port! Aren't those right about in the right place for the coolant modification??
One thing I was totally unable to do with the available photographs was compare the oil and coolant passages in the head to the various other designs. It seems to me that that comparison would give us a baseline for what kind of block it may have come with, and based upon that the other questions can be deduced.
One final datum to be extracted about your mystery head lies in the intake port, and I must confess a lack of intimate familiarity with the different designs. However, this picture:
is a little bit TOO close to the port; if the camera were slightly further back it would give us a bit more perspective by which to make the comparison to these:
"worked" P90 ports, by BRAAP, this is the pinks head
Virgin E31 intake port courtesy of Noddle, Tasmanian IIRC so this is a pacific market E31 for the record
P90 courtesy of JimZ. Port work has been done but IIRC not a great deal, mostly just around the guide boss and port matching; the CCs on this head looked untouched. I know the entire port has obviously been hit with a grinder, but my memory is telling me that he had done a minimal amount of change other than what was needed to blend the port match and the valve guide work.
E88 port courtesy of Locodrftr, uncertain what work has been done but I think nothing. (Note flashing at 3 and 9 o'clock)
This head needs to get the combustion chambers included in the Head ID thread. (and I STILL haven't gotten around to attempting to condense and organize the data there.. soon!)
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Well, there is no infatuation, the gentleman suggested a 240SX engine (KA24) or an SR20 himself, and I advanced the suggestion of a VG30 as well (since he seemed to like nissan motors.)
The plain reality is that any of those options, Nissan and non, 4 through 8 cylinders will require about the same amount of effort to put the driveline in. the Nissan transmissions may be a bit simpler to hang onto the Zcar, but any of the above mentioned engines will require custom mounts.
I am all ABOUT keeping the engine swaps in the family, but they ARE right: the best bang for your buck comes from a Jags That Run SBC V8 conversion. On top of THAT, once you have a SBC in there, your upgradability gets ridiculously simpler...
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You are exactly right, though the problem "is" getting the pistons "to" BDC!
Head is removed, timing chain tensioner tool in place!... Not really a good idea to just rotate the crank at this point...
Well, I caught that part, but is it SO impossible to maintain the timing chain where its at while rotating the crank through 30 degrees? You caught me, I haven't had my head off yet, OR dickered with a timing chain. My 4 1/2 years of DDing never included timing chain work, or even a valve adjustment (though I have gotten THAT one out of the way since then.)
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Bob, seafoam that engine.
Add some to the fuel, add some to the motor oil (act like it is ATF/high detergent motor oil) and then suck some thru the vacuum lines. I think its actually ridiculously easy to seafoam carb'd cars, you just gotta get the air intake to suck it up somehow.
Change the spark plugs while you are at it. I;ve seen a few good old NGK BPR6ES11s lately that failed for no good reason other than living a tolerable (20K) lifespan.. they look good, they arent so old that you'd think they were a problem, but sure enough....
Otherwise... a 240SX engine and trans would be simple enough to install but you would likely want to turbocharge it before too long. a 300ZX driveline comes to mind as well.
If you really think you've got the horse sense, then seriously, consider trying to get a turbo'd L28 engine together under megasquirt. http://www.diyautotune.com read up on it and think about it like this.. if you can stop the smoke then you've got all the time in the world to find the right buy in the right location. OR, you could read enough to determine that your rebuilt Ztherapy SUs, a new cam, and a nice hot ignition system would suffice for enough pep to settle you down.
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Don't give up Webers! I did and I miss them dearly. I had them on my Alfa Romeo and still hope to build a Tripple L24 some day. Your problem is that you are measuring AFR's! Webers are more of a seat of the pants kind of thing. (tongue in cheek). Keep up the great research! I will need this info someday.
Webers "talked" to me. Fuel injection doesn't.
You need to speak the right language!!! 010011011101011010101!!!! aahahahaha!!!!
sorry.
What about modding some Mikuni/Solexes to use weber jets so you get the tunability of the weber jetting selection, but the drivability of the solexes.. (solexes have this low vacuum enrich circuit, don't they? I am teaching myself about carbs finally and know there was a drivability reason my uncle tended towards solexes in his roadsters and his Z rather than webers..)
In my mind I've always put the Mikuni before the weber simply because it was a factory option on the roadsters.... but at the same time I have long since adapted the common lingo of just calling them all "triple webers." TBH, I've really got next to no idea what the detailed differences between them are..
to the Google Cave!!!
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Wait a second... it seems that its almost DEFINITELY a stroker at this point and we are trying to figure out how MUCH of a stroker (LD crank or LD crank turned for even MORE than 3.1)
So why not just get one piston at BDC and measure from the crown of the piston (whatever plane on the piston is even with the deck at TDC) to the top of the firing deck????
If deck clearance is perfectly flush, then the stroke is the distance from the top of the cylinder wall down to the crown of the piston at BDC, right???
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I suspect it something to do with the ramps being poorly designed or the recommended lash being all wrong.
JM might be able to do something with it...he loves 'em big and lumpy
Yuk @ end comment..
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I'd keep it between my driver seat and the center console for use as a theft-deterrent. Maybe a little grip tape on one end, and an old timing gear on the front
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^ Calling peta now.
Just don't call the Board of Health!!
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Well my thinking is that the camshaft could be one of three things:
Improperly Dialed In;
Improperly matched to your stroker motor/carb tune;
A Piece Of Worthless Junk; An Anti-Theft Device (hefty club, *bludgeon*)
My guess is the second one; hence me reaching for the opposite of a stroker (L24) and wondering if it would be happier with that. Some small venturis, some rich jets, some high compression, and some octane, I think that cam might be more than a funky baseball bat.
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I worked for... a restaurant once. Place had a NASTY roof rat problem. I was a delivery driver, and my assistant manager was my buddy, and we frequently closed the place together. We worked pretty late when we were together, because he and I would be concentrating more, on cleaning and closing up the joint well at night, than on getting out of there quickly. Anyhow, every time we went outside for a cigarette break after hours were over (and equipment was off and cooling) the rats came out in force, and sometimes we would be playing hockey/soccer with them. We caught a couple.
The first one we caught, we didn't know what to do with. Wound up putting it in a trash bag, wrapping it up, and setting the bag behind the wheel of my car. Popped the tranny into neutral, pushed back.. ugh.
I'm a big time animal lover; I spent many years working as a veterinary technician too. I still hate rats. that wasn't easy or fun to do. Needless to say, we caught fewer rats than we could after that first one.
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Could that be the Maxima N47 head? (I forget what the exhaust ports are on that one) Barring that, I agree with the P90 argument, unless it is some Non american market head.
*I* want to know what your original camshaft was ground for... At this point I am betting you've got a full stroker motor (those pistons ARE very nice looking
) and I would imagine that such a narrow lobe, that ramps up so high, would be laborious for that engine to run on.. I wonder what that skinny cam would do in an L24 with a valvetrain to run up to 7500 every time and some triple 40's with narrow chokes would sound like....... -
Many thanks!!! I agree with you on the gauges, so it is good to know that you guys have done the leg-work to make these particular Nissan Lego Bricks fall into place.
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Local Nissan parts counter is where I purchase ALL of my L-series lash pads... Actually, I call them, tell em what thickness and how many, they deliver them to my door.
'Ts good to be da King!!
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OMG somewhere there is a parts warehouse guy who just lost half of his flattop parts hoard..... I hope he is handling it okay.
In case you couldn't tell, you might have the only pictures on all of the internet of freshly rebuilt boat anchors
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...and the reason THAT thing runs so well on low octane and high compression is the rod/stroke ratio!!!Isn't that also a main factor of compression ratio? Hopefully I don't sound dumb, because some of these concepts are new to me, but rod/stroke affects piston speed, and there for chamber pressure..? Or, if you physically change stoke, that directly affects your comp. ratio? right?
<--confused
It is a very complex thing that I have only gathered an understanding of through reading about. I just migrated to a new PC and can't get all of my bookmarks the easy way, so I cannot link you to any of the great articles that can explain a whole lot, and my understanding isn't yet so solid that I can explain the how and why. The point I was trying to make, was to illustrate that there is no cut and dry "rule" about it, but instead certain engine/engine families have certain tendencies that get discovered over time, regarding combinations of the factors I illustrated and probably more that I forgot or don't even know about yet.
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There is no fuel rail. I'll be using individual lines to each injector. I'm trying to get a mechanical injection look with the individual lines.
Derek
I do not know if I had heard this detail before, and have forgotten it, or if this is the first time.. but I LOVE it.
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what do you weigh?? 2750 minus 180 for you and say, 40 pounds for about 7-8 gallons of fuel, is only 2530 pounds.. Not TOO bad, and 180 was a guess. If you are bigger than 210#, well, then.... your car is under 2500! It takes some doing to shed weight, and 2500 is right where a seater 280Z normally sits.
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Enjoy it, its a clunky, antiquated, 40 year old 3 speed automatic transmission. BTW, that thread linked to above at z31.com pertains to z31 4 speeds.. while that transmission DID evolve from the 3 speed in the S30, they aren't the same animal, and most of the thread was beating the dead horse of "what can you do to this automatic transaxle" into the dirt.
I know you can swap the bellhousing off of the stock manual gearbox onto the manual gearbox from a 240SX. The automatic trans from the 240SX is the "grandchild" of the 3 speed in your Z-car. who knows? you might get lucky
If you want to learn about these transmissions some (not a GREAT deal of help but it shows you the heritage involved and the vehicles they are in) look up 280ZX in wikipedia, and look at the section on the right side where they run through a bullet list of vehicle specs. There is a link there to "jatco 3n71" automatic transmission.. the 4n71 was in the earlier 300ZX, and then the 240SX slushbox was the 4r01. Maybe you could use one of those?? The hardbody pickups used that same box, too, and there was a "medium dudty" one available (some hardbodies/pathfinders and all 240SX)
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i hear the keys a-jangling already..
Keep searching. you just described the stock turbo motor, except only the P90 and P90a heads were used for turbos, and they have the square port exhaust, so finding a round port turbo header for the P79 might be a chore (or might not, depends on how lucky you get.)
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Was the car running before you changed fuel pumps??
I'm going to guess no, and I am also going to guess that the old fuel pump wasn't pumping either, and I am going to guess that something is up with your fuel pump relay. This problem could be with the relay, it could be with a wire, or it could be in your AFM.
Do yourself a favor and look up "EFI Bible." It contains all the answers you seek. google xenons30 if you can't find it here.
Keep up the great research! I will need this info someday.
) and I would imagine that such a narrow lobe, that ramps up so high, would be laborious for that engine to run on.. I wonder what that skinny cam would do in an L24 with a valvetrain to run up to 7500 every time and some triple 40's with narrow chokes would sound like....... 
My 260Z project (No 56K)
in S30 Series - 240z, 260z, 280z
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Aww, bummer!!!! All that work into the SU carbs and blam, bent valve.
At least you know youve got good carbs when you get the thing thrown together right.....